Glaucoma, a group of eye diseases affecting the retina and optic nerve, is one of the leading causes of blindness worldwide. Most forms of glaucoma result when the intraocular pressure (IOP) increases to pressures above normal for prolonged periods of time. IOP can increase due to high resistance to the drainage of the aqueous humor relative to its production. Left untreated, an elevated IOP causes irreversible damage to the optic nerve and retinal fibers resulting in a progressive, permanent loss of vision.
FIG. 1 is a diagram of the front portion of an eye that helps to explain the processes of glaucoma. In FIG. 1, representations of the lens 10, cornea 20, iris 30, ciliary body 40, trabecular meshwork 50, and Schlemm's canal 60 are pictured. Anatomically, the anterior segment of the eye includes the structures that cause elevated IOP which may lead to glaucoma. Aqueous humor fluid is produced by the ciliary body 40 which lies beneath the iris 30 and adjacent to the lens 10 in the anterior segment of the eye. This aqueous humor washes over the lens 10 and iris 30 and flows to the drainage system located in the angle of the anterior chamber. The angle of the anterior chamber, which extends circumferentially around the eye, contains structures that allow the aqueous humor to drain. The trabecular meshwork 50 is commonly implicated in glaucoma. The trabecular meshwork 50 extends circumferentially around the anterior chamber. The trabecular meshwork 50 seems to act as a filter, limiting the outflow of aqueous humor and providing a back pressure that directly relates to IOP. Schlemm's canal 60 is located beyond the trabecular meshwork 50. Schlemm's canal 60 is fluidically coupled to collector channels (not shown) allowing aqueous humor to flow out of the anterior chamber. The two arrows in the anterior segment of FIG. 1 show the flow of aqueous humor from the ciliary body 40, over the lens 10, over the iris 30, through the trabecular meshwork 50, and into Schlemm's canal 60 and its collector channels.
One method of treating glaucoma includes implanting a drainage device in a patient's eye. The drainage device includes a pathway through which aqueous flows from the anterior chamber in the eye to a drainage site, relieving excessively high IOP pressure. In some instances however, over the course of treatment with the drainage device, debris or deposits may accumulate or build-up in the flow pathway. These debris and deposits may eventually decrease the flow capacity of the drainage device. This in turn may decrease the effectiveness of the drainage device as a treatment for elevated IOP.
The system and methods disclosed herein overcome one or more of the deficiencies of the prior art.